Soon, it will cost just 435 pounds to keep tab on your ageing process. Scientists have developed a blood test, which can show the speed of ageing and give an estimate of how long a person is going to live.

The test results may be vital to life-insurance companies offering medical cover that depends on a person's lifetime risk of falling seriously ill or dying prematurely.

The controversial blood test is to go on sale to the general public in Britain later this year.

The test has been designed to measure vital structures on the tips of a person's chromosomes called telomeres, which scientists believe are one of the most important and accurate indicators of the speed at which a person is ageing.

According to scientists, the test will be able to tell whether a person's "biological age", as measured by the length of their telomeres is older or younger than their actual chronological age.

"We now that people who are born with shorter telomeres than normal also have a shorter lifespan. We know that shorter telomeres can cause a shorter lifespan," the Independent quoted Maria Blasco, of the Spanish National Cancer Research Centre in Madrid as saying.

"But we don't know whether longer telomeres are going to give you a longer lifespan. That's not really known in humans," she added.

Scientists are hopeful that the test could prove to be a breakthrough in satiating the curiosity of the people regarding their mortality, who can accordingly, plan their life.

However, scientists do not yet believe that the test predictions can be narrowed down to calculate the exact number of months and years a person has yet to live.